原铝生产流程温室气体排放主要影响因素的关联度分析

铝是国民经济建设和发展的关键基础材料,然而由其生产过程所产生的大量温室气体排放也逐渐成为政府关注的焦点。本研究计算了我国原铝生产不同年度的生命周期能耗和温室气体排放量,并分析了资源消耗和生产工序能耗等影响因素与温室气体排放的关联性。结果表明,在各年原铝生产的温室气体排放总量中,电力和阳极效应导致的排放所占比重分别为68.5%和7.9%,其他影响因素所占比重均低于6%;与温室气体排放关联度最高的3个影响因素依次是电耗、煤气燃烧和石灰石煅烧,其值分别为0.937、0.899和0.893;在目前铝电耗和阳极效应控制水平提升空间有限的情况下,降低煤气的消耗,提高石灰石的使用效率,是实现原铝生产温室气体减排的有效途径。     

计算机软件模拟油罐火灾对环境的影响

通过应用火灾模拟软件FDS,建立了某油库稳定燃烧的数学模型,并研究了在风速为8 m/s的实验条件下,油罐发生火灾时,火焰的发展状况,以及燃烧过程所产生的二氧化碳、一氧化碳和灰尘随时间的变化规律.     

从粉煤灰中提取多种微细氧化物的研究

将粉煤灰与Na2CO3按一定的比例混合后焙烧,采用酸碱联合法提取粉煤灰中氧化硅、氧化铝和氧化铁,分析了工艺条件对粉煤灰中氧化物提取率的影响。实验结果表明,从粉煤灰中提取氧化物的最佳条件是:碳酸钠与粉煤灰的比例0.6∶1.0,焙烧温度850℃、盐酸浓度4 mol/L,氢氧化钠浓度2.6 mol/L,浸取时间约6 h。在此条件下得出微细氧化硅、氧化铝、氧化铁的晶体,其平均粒度分别为氧化硅1.107μm,氧化铝1.334μm,氧化铁0.783μm。     

Distribution of atrazine in a crop-soil-groundwater system at Baiyangdian Lake area in China

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Production of N2O in two biologic nitrogen removal processes: a comparison between conventional and short-cut nitrogen removal processes

The N2O production in two nitrogen removal processes treating domestic wastewater was investigated in laboratory-scale aerobic-anoxic sequencing batch reactors （SBRs）. Results showed that N2O emission happened in the aerobic phase rather than in the anoxic phase. During the aerobic phase, the nitrogen conversion to N2O gas was 27.7% and 36.8% of NH＋-N loss for conventional biologic N-removal process and short-cut biologic N-removal process. The dissolved N2O was reduced to N2 in the anoxic denitrification phase. The N2O production rate increased with the increasing of nitrite concentration and ceased when NH＋-N oxidation was terminated. Higher nitrite accumulation resulted in higher NEO emission in the short-cut nitrogen removal process. Pulse-wise addition of 20 mg NO2 -N. L- 1 gave rise to 3-fold of N2O emission in the conventional N-removal process, while little change happened with 20 mg NOS-N L-1 was added to SBR1.     

化工物料包装过程静电危害分析

高绝缘化工物料在包装过程中极易带电,以聚酯切片包装为研究对象,对聚酯切片在输送、包装过程物料静电起电机理进行了分析,并对聚酯切片输送包装过程中的包装袋表面电位及物料荷质比进行现场检测,探讨了聚酯切片打包过程中静电危害及预防措施。     

Millennium-old farm breeding of Chinese softshell turtles (<Emphasis Type="Italic">Pelodiscus</Emphasis> spp.) results in massive erosion of biodiversity

Chinese softshell turtles (Pelodiscus spp.) are widely distributed, ranging from the Amur and Ussuri Rivers in the Russian Far East through the Korean Peninsula, Japan, and eastern, central, and southern China to southern Vietnam. In East and Southeast Asia, Chinese softshell turtles are traditionally exploited for food and have been farm-bred in China since the Spring and Autumn Period, more than 2400 years ago. Currently, the annual production of Pelodiscus amounts to 340,000 t in China alone. Using mitochondrial DNA (2428 bp) and five nuclear loci (3704 bp), we examined broad sampling of wild and farm-bred Pelodiscus to infer genetic and taxonomic differentiation. We discovered four previously unknown mitochondrial lineages, all from China. One lineage from Jiangxi is deeply divergent and sister to the mitochondrial lineage of Pelodiscus axenaria. The nuclear loci supported species status for P. axenaria and the new lineage from Jiangxi. Pelodiscus maackii and P. parviformis, both harboring distinct mitochondrial lineages, were not differentiated from P. sinensis in the studied nuclear markers. The same is true for two new mitochondrial lineages from Zhejiang, China, represented by only one individual each, and another new lineage from Anhui, Guangdong, Jiangxi and Zhejiang, China. However, Vietnamese turtles yielding a mitochondrial lineage clustering within P. sinensis were distinct in nuclear markers, suggesting that these populations could represent another unknown species with introgressed mitochondria. Its species status is also supported by the syntopic occurrence with P. sinensis in northern Vietnam and by morphology. In addition, we confirmed sympatry of P. axenaria and P. parviformis in Guangxi, China, and found evidence for sympatry of P. sinensis and the new putative species from Jiangxi, China. We also discovered evidence for hybridization in turtle farms and for the occurrence of alien lineages in the wild (Zhejiang, China), highlighting the risk of genetic pollution of native stock. In the face of the large-scale breeding of Pelodiscus, we claim that the long-term survival of distinct genetic lineages and species can only be assured when an upscale market segment for pure-bred softshell turtles is established, making the breeding of pure lineages lucrative for turtle farms. Our findings underline that the diversity of Pelodiscus is currently underestimated and threatened by anthropogenic admixture. We recommend mass screening of genetic and morphological variation of Chinese softshell turtles as a first step to understand and preserve their diversity.     

市区餐饮娱乐业环境管理浅见

本文从实际出发对市辖区餐饮业这个突出的环境敏感问题，查摆了现象，分析了产生原因，结合现阶段市辖区餐饮业环境管理实际，提出了针对性整改的措施。     

酸雨作用下中亚带森林冠层淋溶规律研究

2001年1月～2002年6月对韶山亚热带常绿阔叶林4个采样区进行了酸雨的监测,以监测数据为依据,分析研究了林内穿透水中主要离子的淋溶规律。结果表明:大气降水经过森林冠层后pH值明显升高,韶山亚热带常绿阔叶林对SO42-、NO3-、Mg2+、NH4+离子具有吸收作用,特别是NH4+和NO3-离子。SO42-、Ca2+和Mg2+离子的冠层淋溶百分率随降雨量的增加有明显减少的趋势。Ca2+、K+和Cl-随着pH的增加,其冠层淋溶百分率呈增加趋势。韶山地区在常年酸沉降作用下,森林冠层对酸性离子SO42-、NO3-的吸收作用最强。根据18个月离子浓度平均值来计算,韶山地区森林冠层离子的淋溶序列为:K+>Ca2+>Cl->Mg2+>SO42->NO3->NH4+>Na+。